Rebuild Kits, Gaskets & Seals

200,000 Miles Is Normal. It Is Not Forever.

Toyota four-cylinders are known for their longevity, and it is no surprise to see a 3RZ well past 200,000 miles still running. Nothing lasts forever, though, and the point of this page is to get a tired one back to being a good one.

The Master Rebuild Kit

The Master Rebuild Kit contains what you need to rebuild the engine, and it is assembled from several manufacturers rather than one — we buy each component from whoever makes the best version of it:

• Street Performer hypereutectic pistons (Safety Auto)
• Hastings piston rings (United States)
• Main bearings (Japan)
• Rod bearings
• Thrust bearings (Japan)
• Complete gasket set

It suits a straightforward freshen-up and it suits the base of a more serious build — in the kit's own words, mild or wild.

If you are going further than stock

Hypereutectic pistons are the right choice for a rebuilt street engine and the wrong choice behind boost. If there is a supercharger or a turbo in your plan, move to forged pistons on the Pistons, Rods & Crankshafts page and build the bottom end for the boost rather than around it.

Head Gaskets — OEM or MLS?

Two families, and the choice follows what the engine is going to do.

OEM-style composite seals beautifully on a standard engine and is more forgiving of a deck that is not perfectly flat. The Pro head gasket (OE), and year-specific sets for 1995-1999 and September 2000-2004.

MLS — multi-layer steel handles the cylinder pressure of boost and high compression, and it is what we fit to built engines. It also demands a properly finished deck and head surface; it will not hide what a composite gasket forgives. Available as 97mm bore x .040", 97mm x .051", 96mm x .051" and 96mm x .040".

Match the bore to your block and the thickness to your target compression. A thicker gasket lowers compression, which is usually what you want under boost. If you are not sure, ask before you order — this is not a part to guess at.

Head bolts or head studs

The OE head bolt set is correct for a stock rebuild. For boost, high compression or an MLS gasket, use the Pro head stud set. Studs clamp more evenly and let you torque properly without dragging the threads through the block.

Full gasket sets: complete set, bottom end set, head gasket set and the ITM head gasket set.

Seals — the Parts You Only Get One Chance At

Every one of these is buried behind something expensive to remove. Do them all while the engine is apart.

• Rear main seal — behind the flywheel. Leaving it is how a fresh engine ends up leaking onto a new clutch.
• Front balancer seal and the Seal Saver harmonic balancer seal — the Seal Saver is the answer when the balancer itself has worn a groove and a standard seal will just leak again.
• Seal Saver rear main for the same problem at the back.
• Valve cover gasket — cheap, and the commonest oil leak on a high-mileage 3RZ.
• Oil filter housing seal kit — frequently mistaken for a rear main leak.

Also here: brass freeze plugs, a sensible upgrade over steel while the block is bare, and the head-to-block dowel pin.

The Balance Shafts: the One Known Weakness

The 3RZ-FE is a genuinely tough engine. It has one recurring bottom end problem, and it is the counterbalance shaft assembly. If the engine is apart, this is the moment to deal with it.

We will put our position plainly: we prefer to see the balance shafts removed. They are one of the only common bottom end issues with these engines, and deleting them takes the failure out of the engine permanently.

The Balance Shaft Removal Kit is a complete job in a box rather than a set of blanking plates:

• New bearings and replacement inserts
• A billet aluminium install driver
• An oil squirter to keep the chain properly lubricated once the shafts are gone
• Drill bit and tap to plug the oil galley

That oil squirter is the detail that matters. Removing the shafts changes how oil reaches the chain, and a delete that ignores it trades one problem for another.

It suits everything from a completely stock engine to a full race build. There is no minimum spec at which it starts making sense.

What you lose, honestly

Balance shafts exist to cancel secondary vibration in a large four-cylinder. Take them out and the engine is measurably less smooth at idle and light throttle. Most owners find it a fair trade for removing a known failure; some do not. If your truck is a quiet daily commuter and the engine is healthy, leaving them alone is a defensible choice.

If you would rather keep them and simply service them, the balance shaft bearings are sold as a set of four, and the billet remove and install tool makes the job possible without damaging the bores.

One consequence to carry forward: if you delete the shafts, you want the Basic timing chain kit, not the Standard — the Standard includes counterbalance parts you have just removed. The three kits are explained on the Timing Components page.

Three Things to Do While It Is Apart

1. Delete the balance shafts. The one common bottom end issue on this engine, and a fraction of the cost now versus later — the kit is above.
2. Do the timing chain properly. If you delete the balance shafts, buy the Basic chain kit, not the Standard.
3. Replace the water pump. Same front cover, and it is the wrong part to be doing again in a year — see Cooling.

Rebuilding, or wondering whether to? Tell us the mileage and symptoms and we will tell you honestly whether it needs a rebuild, a head, or just a valve cover gasket.